Ignore zero-byte JS keyboard files

For the 3rd part of #370, ignore 0-byte JS files in `KMManager.getLatestKeyboardFileVersion)`

If a keyboard doesn't have a valid version, attempting to load it will revert to the default (EuroLatin2) keyboard.

Also added a check so null version keyboard doesn't get added to OldKeyboardsList

Rename references to tavultesoft.keymanweb in KeymanWeb compiler and debugger

Update HttpURLConnections to follow HTTPS redirects

Check valid file size when downloading keyboard

New class will manage the HttpUrlConnection

Addresses the second part of #370

For the first portion of resolving issues/370

Fix KMManager and JSONParser HttpURLConnection calls so HTTP:// to HTTPS:// redirects are properly followed.

Add version 10.0 keyboard support for Mac

Add version 10.0 support for Delphi kmx libraries

[Web] Keystroke control path rework

[Web] Deprecation fixes.

Mac compatibility with legacy apps

Added/enhanced comments related to showPreferences workaround.

Added comment to explain the use of the regex to find a base character to use as the start of the string inserted using the insertText method.

Update history.md for macOS on alpha to match beta

Mac high sierra config workaround

Fixed typo

WIP: This is what I have tried so far. The config window does NOT display when accessed via the menu. It still works (the old/right way) in Sierra when accessed via the About window. If you first try to access it via the menu and then access it via the Configuration button on the About window, it displays twice!

Automatically load images based on screen scale